Paulownia Saplings with Brown Spots: Likely Leaf Spot Fungus

Royal Paulownia saplings (Baton Rouge, LA) develop brown spots on lower leaves → yellow → drop. High heat/humidity. Photos show progression. Phyllosticta, Sphaceloma, or anthracnose?

Diagnosis: Fungal Leaf Spot

Symptoms + climate = classic leaf spot complex. Lower leaves hit first (splash dispersal, humidity).

Treatment

1. Broad-spectrum fungicide now (chlorothalonil, copper, or mancozeb).
2. Critical: Spray at budbreak next spring (protect new leaves).
3. Cultural: Water at base only; improve air flow; remove fallen leaves.

Paulownia grows fast—it will outpace this with preventive sprays.